Polymeric latices and sodium aluminate

ABSTRACT

A coating composition comprising from 1 to 99 percent by weight of sodium aluminate and from 1 to 99 percent by weight of a water-in-oil emulsion, said emulsion containing dispersed therein from 1 to 35 percent by weight of a finely divided water-soluble anionic vinyl addition polymer.

United States Patent 1191 Anderson 1 Aug. 28, 1973 POLYMERIC LATICES ANDSODIUM 3,057,811 10/1962 Trachterbury et a1 260/29.6

ALUMINATE 3,511,798 5/1970 Jsoarson et a1. 260/29.6

3,624,019 11/1971 Anderson 260/29.6 [75] inventor: Donald R. Anderson,Oswego, I11. [73] Assignee: Nalco Chemical Company, Chicago, PrimaryExaminer-Melvin Goldstein 11]. Assistant Examiner-Peter F. Kulkosky [22]Filed: Jan. 31, 1972 AztorneyJohn G. Premo et a1.

Appl. No.: 222,340

U.S. Cl 260/29.6 M, 117/152, 117/161 UZ Int. Cl. C08f 37/00 Field ofSearch 260/29.6 M

References Cited UNITED STATES PATENTS 10/1959 Rokowitz 20/296 ABSTRACT4 Claims, No Drawings POLYMERIC LATICES AND SODIUM ALUMINATEINTRODUCTION Many attempts have been made to prepare coatingcompositions in the form of films which may be cast on such surfaces asglass, metals, or they may be formed on the other substrates such as awide variety of fibers such as cloth, paper and the like. The coatingscan be formed into suitable coatings for the protection ofa variety ofsurfaces against the attack of many chemical substances.

INVENTION The invention relates to a coating composition comprising:

A. Sodium aluminate having a concentration from 1 to 99 percent byweight; and

B. A water-in-oil emulsion having a concentration from 1 to 99 percentby weight, said emulsion containing dispersed therein from 0.1 to 35percent by weight of a finely divided water-soluble anionic vinyladdition polymer.

The preferred coating compositioncomprises:

A. Sodium aluminate having a concentration from 10 to 40 percent byweight; and

B. A water-in-oil emulsion having a concentration from 60 to 90 percentby weight, said emulsion containing dispersed therein from 0.1 to 35percent by weight of a finely divided water-soluble anionic vinyladdition polymer.

The water-soluble anionic vinyl addition polymers that are used in thepractice of the invention may be illustrated by the following list ofpolymers:

"TABLE I No. Polymer 1 Polyacrylic acid-sodium salt 2 Polymethacrylicacid-sodium salt 3 Maleic anhydridevinyl acetete copolymer 4 Polyvinylmethyl ether-maleic anhydride copolymer 5 Methacrylic acid-acrylamidecopolymer 6 Polyacrylic acid 7 lsopropenyl acetate-maleic anhydridesodium salt 8 Itaconic acidvinyl acetate 9 Methyl styrene-maleicanhydride sodium salt 10 Styrene-maleic anhydride 1 1Methylmethacrylate-maleic anhydride sodium salt [2 Acrylic acid-styrenel3 Acrylamide-acrylic acid (5 percent by weight) 14 Acrylamide-acrylicacid (50 percent by weight) 15 Polystyrene sulfonic acid 16Acrylamide-acrylic acid (80 percent by weight) The above polymers mayvary in molecular weight. They may be as low as 10,000 or as high as 12million or more. In many of the more useful applications, which will bemore fully discussed hereafter, the molecular weight will be greaterthan I million.

The invention contemplates using as preferred watersoluble anionic vinyladdition polymers the homoand copolymers of acrylic acid as well as thewater-soluble salts thereof.

A preferred water-soluble anionic vinyl addition polymer of thisinvention is acrylamide-sodium acrylate copolymer wherein the ratio ofacrylamide to sodium acrylate is 65:35.

Another preferred water-soluble anionic vinyl addi tion polymer is anacrylamide-meth acrylic acid copolymer in a ratio of 90:10.

THE VINYL ADDITION POLYMER POLYMERIC LATEX The invention contemplatesutilizing the watersoluble vinyl addition polymers in the form ofwater-inoil emulsion which contains dispersed therein the water-solubleanionic vinyl addition polymer. Emulsions of this type are prepared bydispersing the anionic vinyl addition polymer into a water-in-oilemulsion. These polymers as produced by most manufacturing processes arein the form of powders or lump-like agglomerates of varying particlesize. It is desirable that the particles, before being placed into theemulsion, be comminuted by grinding, abrading or the like so that theiraverage particle size is less than 5 millimeters and preferably iswithin the range of l to 5 microns. After the powders have beencomminuted, they may be dispersed into the water-in-oil emulsion bymeans of agitation provided by such devices as stirrers, shakers and thelike. To be commercially practical, the amount of polymer in theemulsion should be at least 2 percent by weight. The inventioncontemplates using emulsions containing between 5 to percent by weightwith preferred emulsions having a polymer concentration within the rangeof 10 to 45 percent by weight. In some cases the starting emulsions areconverted to suspensions due to the nature and the amount of the polymerpresent therein.

From a commercial standpoint it is beneficial that the polymer emulsionsthus described be stable, yet at the same time contain relatively largeamounts of polymers. One method of insuring that the polymers do notprecipitate when dispersed in the emulsion is that the particle size ofthe polymer be as small as possible. Thus polymers dispersed in theemulsifiers are quite stable when the particle size is within the rangeof 5 millimicrons up to about 5 microns. To produce particle sizeswithin these limitations, spray dryers with appropriate size nozzles maybe used. It also is possible to prepare the polymer-containingerriulsion of the watersoluble anionic vinyl addition polymers directlyfrom the vinyl monomers from which these polymers are synthesized. Suchpolymer-containing emulsions may be synthesized by using thewater-in-oil emulsion polymerization technique set forth in U.S. Pat.No. 3,284,393. The teachings of this patent comprise forming awater-in-oil emulsion of water-soluble ethylenic unsaturated monomers.The emulsion is formed by utilizing a water-in-oil emulsifying agent. Tothis monomer is added a free radical-type polymerization catalyst andthen heat is applied under free radical-forming conditions to formwater-soluble polymer latices. The polymeric latices produced by thispatent are relatively unstable and frequently must be treated withadditional emulsifiers to render the products stable.

The water-in-oil emulsions used to prepare the above polymers may beformulated by any number of known techniques.

The oils used in preparing these emulsions may be selected from a largegroup of organic liquids which include liquid hydrocarbons andsubstituted liquid hydrocarbons.

A preferred group of organic liquids are the hydrocarbon liquids whichinclude both aromatic and aliphatic compounds. Thus, such organichydrocarbon liquids as benzene, xylene, toluene, mineral oils,kerosenes, naphthas and, in certain instances, petrolatums may be used.A particularly useful oil from the standpoint of its physical andchemical properties is the branch-chain isoparaffinic solvent sold byHumble Oil and Refining Company under the Tradename ISO- PAR M. Typicalspecifications of this narrow-cut isoparaffinic solvent are set forthbelow in TABLE II.

TABLE II Specification Properties Minimum Maximum Test Method Gravity,API at 60/60F 48.0 51.0 ASTM D 287 Color. Saybolt 30 ASTM D I56 Anilinepoint, "F I85 ASTM D 61 I sulfur, ppm ASTM D I266 distillation, F ASTM D86 IBP 400 410 Dry point 496 Flash point, F (Pensky-Martens closed cup)I60 ASTM D 93 Nephelometric mod.

The amount of oil used in relation to the water to prepare the emulsionmay be varied over wide ranges. As a general rule, the amount ofoil-to-water may vary between 511 to 1:10 with preferable emulsionsbeing prepared in the ratio of I11 to 1:10. These ratios areillustrative' of emulsions that can be prepared, although it should beunderstood that the invention is not limited thereby.

The emulsions may be prepared by any number of techniques. For example,the emulsions may be prepared by using high speed agitation orultrasonic techniques. In most instances, however, it is desirable thatthe emulsion be a stable emulsion and to achieve this end it is oftennecessary to employ an oil soluble emulsifying agent. The amount ofemulsifying agent to provide an emulsion will have to be determined byroutine experimentation. As a general rule it may be said that theamount of oil soluble emulsifier may range from 0.1 to 30 percent byweight based on the weight of the oil. To produce stable emulsions theamount of emulsifier will normally be within the range of 12 to percentby weight of the oil.

Rather than provide a listing of suitable emulsifiers, recommended asbeing satisfactory are the so-called low HLB materials which are welldocumented in the literature and are summarized in the Atlas HLBSurfactant Selector. Although these ,emulsifiers are useful in producinggood water-in-oil emulsions, other surfactants may be used as long asthey are capable of producing these emulsions. For instance, we havefound that certain high I-ILB surfactants are capable of producingstable water-in-oil emulsions. A typical low HLB emulsifier is sorbitanmonooleate.

PREPARATION OF THE COATING COMPOUND Once latices containing thewater-soluble anionic vinyl addition polymers are prepared the sodiumaluminate is combined therewith by the utilization of conventionalmixing techniques. Preferably the sodium aluminate is in the form of anaqueous solution containing to 75 percent by weight and is added to thepolymeric latex. After uniformly mixing the two components there resultsa liquid dispersion of a water-soluble vinyl polymer emulsion and sodiumaluminate.

To illustrate the preparation of the coating composi tion, a variety ofemulsions were prepared containing different water-soluble vinyladdition polymers. These emulsions are set forth below in TABLE III.

TABLE III Water Phase y Wt) Oil Phaset by Wt) In polymer Emulparticlesion size Range III 72 28(T) 35% nos-7.0,

Methacrylic Acid 32% 30p. Acrylamide 3O Acrylic Acid Sodium PolyacrylateVI 7I 29(I) 37% l mm.

I= ISOPAR M T Toluene COMPOSITION A To emulsion in Table III,Composition Number I, there was added 50 percent by weight of an aqueoussolution containing 42 percent by weight of sodium aluminate. Afterapproximately 10 minutes, the emulsion had inverted and the polymer wasin solution forming a gel-type material.

COM POSITION B To grams of Composition Number VI in Table III, there wasadded 100 grams of 42 percent aqueous solution of sodium aluminate. Thepolymer went into solution within l0 minutes forming a gel-typestructure.

To illustrate other novel dispersions of the invention, TABLE IV ispresented below:

TABLE IV latex Na Time to compo from by NA aluminate form gel sitionable III wt. aluminate (by wt) structure C I 60 42% 40 8 min.

soIution D VI 50 42% 50 10 min.

solution E V 70 42% 30 5 min.

solution INVERSION OF THE DISPERSION The finished coating composition isstable generally for only a short period of time. Upon dispersion ofsodium aluminate in the polymeric latex the emulsion begins to invertthereby releasing the finely-divided water-soluble anionic vinyladdition polymer into solution. This reaction between the highlyalkaline sodium aluminate solution and the polymeric latex produceswithin a matter of minutes a reaction product which may be described asa three-dimensional, water and hydrocarbon liquid insoluble gel-likestructure. These gellike structures are spongy, porous, and aresubstantially incapable of adherence to most hydrophobic surfaces. Theymay be prepared from dilute solutions of the liquid dispersions in theform of films which may be cast on such surfaces as glass, metals, orthey may be formed on to other substrates such as a wide variety offibers such as cloth, paper and the like.

The sodium aluminate containing polymeric latex may be inverted by anynumber of means. A surfactant may be added to either thepolymer-containing emulsion or to the sodium aluminate into which it isto be added. The placement of a surfactant into the sodium aluminatecauses the emulsion to rapidly invert and release the polymer in theform of an aqueous solution. When this technique is used to hasten theinversion of the sodium aluminate-polymer-containing emulsion the amountof surfactant may vary over a range of 0.01 to 50 percent based onpolymer. Good inversion often occurs within the range of 1.0 to percentbased on polymer.

The preferred surfactants are hydrophilic and are further characterizedas being water-soluble. Any hydrophilic-type surfactant such asethoxylated nonyl phenols, ethoxylated nonyl phenol formaldehyde resin,dioctyl esters of sodium sulfosuccinate, and octyl phenol polyethoxyethanol can be used.

Other surfactants that may be employed include the soaps such as sodiumand potassium myristate, laurate, palmitate, oleate, stearate, resinate,and hydroabietate, the alkali metal alkyl or alkylene sulfates, such assodium lauryl sulfate, potassium stearyl sulfate, the alkali metal alkylor alkylene sulfonates, such as sodium lauryl sulfonate, potassiumstearyl sulfonate, and sodium cetyl sulfonate, sulfonated mineral oil,as well as the ammonium salts thereof; and salts of higher means likelauryl amine hydrochloride, and stearyl amine hydrobromide.

Any anionic, cationic, or nonionic compound can be used as thesurfactant.

In addition to using the water-soluble surfactants described above,other surfactants may be used such as silicones, clays and the likewhich are included as surfactants since, in certain instances, they tendto invert the emulsion even though they are not water-soluble.

In other specific cases the surfactant may be directly added to thepolymer-containing emulsion; thereby rendering it self-inverting uponcontact with water which contains the sodium aluminate.

Other techniques for increasing the inversion of the emulsions includethe use of agitation, high voltage electrical fields and heat. For anyparticular polymercontaining emulsion a suitable method for itsinversion may be readily determined by routine experimentation.

The Compositions A through E, as prepared above, formed an opaquerubbery-like gel that was insuluble in water and in most common organicsolvents, e.g., pentane, methanol, xylene and the like.

When the sodium aluminate was added to the polymeric latex, thedispersion was not stable after a short period of time. The emulsionbegan to invert and the polymer was released into the solution. The gelwas allowed to air dry for 3 days. At the end of this time the structurebecame more rubbery and had shrunken considerably in size due to loss ofliquid. It was still semiflexible and was difficult to pull apart.

Composition C was roller coated onto a sheet of glass and a piece ofcotton cloth. After setting the produced film was washed with pentane toremove the organic solvent. The films produced on both the glass and thecotton cloth rendered the surfaces resistant to oil staining.

It is believed that the gel-like structures are formed when theisoelectric point of the inverted water-soluble vinyl addition polymerand the sodium aluminate is reached. The exact amount of either thepolymer or so dium aluminate to effectively neutralize one another isdifficult to determine. When the ratios of either ingredient exceed theamount needed to exactly neutralize the other substantial quantities ofthe component in excess is believed to be entrapped by the gel-likestructure. Thus, by varying excesses of the polymer or sodium aluminateit is possible to produce a neutral gellike structure which hasentrained within its interstices excesses of polymeric material thatwill impart strength and resilience to the gel-like structure. Thiseffect allows the structures to be coated or adherently bonded to manyhydrophilic surfaces by means ofionic or polar attractive forces.

In preparing the porous gel-like structures from the liquid dispersionsof the invention it is possible to add other chemicals to the dispersionjust prior to or at the time of inversion. When such a technique is usedit is possible to entrap many chemicals within the gel-like structurewhich would be released under certain circumstances. For instance, slowrelease of corrosion inhibitors, bactericides, herbicides, and the likemay be prepared.

Having thus described my invention, 1 claim:

1. A coating composition comprising:

A. Sodium aluminate having a concentration of from 10 to 40 percent byweight; and

B. A water-in-oil emulsion having a concentration from 60-90 percent byweight, said water-in-oil emulsion being comprised of:

1. water ranging between 5 and 40 weight;

2. a water-soluble anionic vinyl addition polymer having a concentrationbetween 20 and 40 percent by weight;

3. a hydrophobic liquid ranging between 5 and 35 percent by weight; and

4. a water-in-oil emulsifying agent having a concentration between 0.1and 30 percent by weight.

2. The coating composition of claim 1 wherein the polymer is anacrylamide-sodium acrylate copolymer.

3. The coating composition of claim 2 wherein the weight ratio ofacrylamide to sodium acrylate is 65:35.

4. The coating composition of claim 1 wherein the polymer is anacrylamide-methacrylic acid copolymer. i

percent by

2. The coating composition of claim 1 wherein the polymer is anacrylamide-sodium acrylate copolymer.
 2. a water-soluble anionic vinyladdition polymer having a concentration between 20 and 40 percent byweight;
 3. a hydrophobic liquid ranging between 5 and 35 percent byweight; and
 3. The coating composition of claim 2 wherein the weightratio of acrylamide to sodium acrylate is 65:35.
 4. The coatingcomposition of claim 1 wherein the polymer is an acrylamide-methacrylicacid copolymer.
 4. a water-in-oil emulsifying agent having aconcentration between 0.1 and 30 percent by weight.